This thesis addresses the development of GaN (Gallium Nitride) technology, which is crucial for the European Union’s radar and telecommunication sectors, especially for high-frequency applications like 5G and military systems. The research focuses on enhancing GaN transistors to operate efficiently at millimeter-wave frequencies by optimizing structural components, including a sub-150 nm gate length and ultrathin AlN barriers. Different GaN structures with an AlN barrier were evaluated for performance, thermal stability, and reliability under DC and RF conditions, demonstrating strong stability up to 200°C. The inclusion of an AlGaN back-barrier improved electron confinement and reduced trapping, enhancing the devices’ performance and robustness, particularly under DC and RF stress. The AlGaN back-barrier provides better stability in leakage currents and static I(V) curves, reduces trapping and self-heating effects, and extends the operational DC-SOA. The study concluded that AlGaN back-barriers significantly increase the reliability and lifespan of GaN HEMTs (High Electron Mobility Transistors) for high-power, high-frequency applications, advancing their readiness for future technology applications.
